For Battle Royale players, Epic is delivering some new skins perfect for the Hallmark funded Valentine's day. These include a cupid sculpture skin, and a skin-tight teddy bear skin that kind of reminds me of a demented Carebear crossed with Deadpool.
Fortnite Battle Royale is also adding a new, Valentine's-themed weapon in the form of a crossbow. Like Cupid's arrow, but deadlier. And since it's silent, it'll let players utilize a little stealth into their game as well.
The Shooting Test #1 has also been switched to Solo only with this patch as Epic is working to fix a known issue where the Shooting Test does not save progression for stats or challenges.
As for Save the World players, they'll also be getting a Valentine's special in the form of a new questline which Epic describes as, "A Love Story, told the Fortnite way." Which presumably means a love store the include zombies and constructions in some form or another.